package com.baomidou.kisso.common.bcprov.util.encoders;


import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStream;

import com.baomidou.kisso.common.bcprov.util.Strings;

public class Base64 {

	private static final Encoder encoder = new Base64Encoder();


	public static String toBase64String( byte[] data ) {
		return toBase64String(data, 0, data.length);
	}


	public static String toBase64String( byte[] data, int off, int length ) {
		byte[] encoded = encode(data, off, length);
		return Strings.fromByteArray(encoded);
	}


	/**
	 * encode the input data producing a base 64 encoded byte array.
	 *
	 * @return a byte array containing the base 64 encoded data.
	 */
	public static byte[] encode( byte[] data ) {
		return encode(data, 0, data.length);
	}


	/**
	 * encode the input data producing a base 64 encoded byte array.
	 *
	 * @return a byte array containing the base 64 encoded data.
	 */
	public static byte[] encode( byte[] data, int off, int length ) {
		int len = (length + 2) / 3 * 4;
		ByteArrayOutputStream bOut = new ByteArrayOutputStream(len);

		try {
			encoder.encode(data, off, length, bOut);
		} catch ( Exception e ) {
			throw new EncoderException("exception encoding base64 string: " + e.getMessage(), e);
		}

		return bOut.toByteArray();
	}


	/**
	 * Encode the byte data to base 64 writing it to the given output stream.
	 *
	 * @return the number of bytes produced.
	 */
	public static int encode( byte[] data, OutputStream out ) throws IOException {
		return encoder.encode(data, 0, data.length, out);
	}


	/**
	 * Encode the byte data to base 64 writing it to the given output stream.
	 *
	 * @return the number of bytes produced.
	 */
	public static int encode( byte[] data, int off, int length, OutputStream out ) throws IOException {
		return encoder.encode(data, off, length, out);
	}


	/**
	 * decode the base 64 encoded input data. It is assumed the input data is valid.
	 *
	 * @return a byte array representing the decoded data.
	 */
	public static byte[] decode( byte[] data ) {
		int len = data.length / 4 * 3;
		ByteArrayOutputStream bOut = new ByteArrayOutputStream(len);

		try {
			encoder.decode(data, 0, data.length, bOut);
		} catch ( Exception e ) {
			throw new DecoderException("unable to decode base64 data: " + e.getMessage(), e);
		}

		return bOut.toByteArray();
	}


	/**
	 * decode the base 64 encoded String data - whitespace will be ignored.
	 *
	 * @return a byte array representing the decoded data.
	 */
	public static byte[] decode( String data ) {
		int len = data.length() / 4 * 3;
		ByteArrayOutputStream bOut = new ByteArrayOutputStream(len);

		try {
			encoder.decode(data, bOut);
		} catch ( Exception e ) {
			throw new DecoderException("unable to decode base64 string: " + e.getMessage(), e);
		}

		return bOut.toByteArray();
	}


	/**
	 * decode the base 64 encoded String data writing it to the given output stream,
	 * whitespace characters will be ignored.
	 *
	 * @return the number of bytes produced.
	 */
	public static int decode( String data, OutputStream out ) throws IOException {
		return encoder.decode(data, out);
	}
}
